Chapter 18: Brain

Hydrocephalus in adults

- keeps pressure within leading to brain damage because it leads to the compression of the brain blood vessels and crushes the soft nervous tissue

Directionality of CSF movement

-Lateral to the Third via interventricular foramen -Third to the Fourth ventricle via cerebral aqueduct

Outside to Inside head:

-Scalp -Epicranial aponeurosis -Loose CT and Periosteum-vascular CT that involves the bone -Cranium -Meninges-CT layers that separate the soft tissue of the brain from the skull -Dura Mater -Arachnoid Mater -Pia Mater-softest, most pliable, attaches to brain itself, on top of cerebral cortex, helps nourish brain cells

Occipital lobe

-after parietal lobe -visual association area -visual cortex -relation to perception of visual stimuli

Lateral ventricles extend from the

-anterior horn located in the frontal lobe to the posterior horn located in occipital lobe and extend to the Inferior horn of lateral ventricle located in temporal lobe -most of the lateral ventricles is located within the parietal lobe

Prefrontal cortex

-anterior to premotor cortex -area related to thinking, trouble solving, concentration, behavior, area where we have personality, morality and judgement

Cerebrum

-biggest part of our brain Gyrus (elevation) Gyri (group of elevation) Sulcus (shallow depression) Sulci, between gyri, gives us different lobes of our brain Fissure (a deep depression)

BBB is absent where?

-choroid plexus-No astrocytes -Hypothalamus -Pituitary gland-major endocrine gland release hormones directly in blood stream -Pineal gland -releases melatonin into blood stream

Peripheral nervous system:

-cranial nerves and spinal nerves -consists of whatever leaves the brain and spinal cord

ependymal cells

-glial cells responsible for producing the CSF , ciliated -function is to take nutrients from blood/blood plasma and make it into CSF

Pituitary gland

-hangs off of/connects to hypothalamus -major endocrine gland -hypothalamus controls the release of hormones by pituitary gland

Hypothalamus

-hypo means below -center of homeostasis -temperature control center -main visceral control center, continuously affects activity of autonomic motor neurons to keep the rate of activity of our internal organs proportional to what our body needs at that specific moment -involved with the thirst center and is known as the brain inner thermostat knows what temperature our body should be causing us to sweat and shiver

Thalamus

-largest nuclei in our brain, thalamus is a group of neuronal cell bodies in one specific area within the CNS

Cerebellum

-little brain, second largest part of our brain -coordination of repetitive body movements (dance, drive a car etc.)

What is the function of the medulla oblongata?

-located under the pons the part that connects the brain and spinal cord -relays sensory information to thalamus and to other portions of the brain stem -regulates reflex centers -autonomic centers for regulation of visceral function (cardiovascular, respiratory, and digestive system activities)

Parietal lobe

-posterior to central sulcus -related to sensations -Postcentral gyrus also called primary somatosensory cortex where we have sensation of the skin, muscles and joints

Arachnoid granulations

-projections that go into the into superior sagittal sinus -extensions of arachnoid mater

Blood Brain Barrier (BBB)

-regulates substances between our blood and the brain tissue -made up of capillary endothelial cells (cells that line inside of capillaries) surrounded by astrocytes (glial cell) -allows nutrients to go in and nourish the brain tissue such as glucose and oxygen -allows CO2 and wastes to get out of brain tissue

What is the function of the pons?

-relay station between cerebrum and cerebellum -regulates respiratory reflex center in medulla

Subarachnoid space

-space between the arachnoid mater and pia mater -true space -we find CSF flowing through which protects our brain creating liquid cushion for brain

Subdural space

-the space between the dura mater and arachnoid mater, -it is a potential space, it is filled with fluid if necessary -in the case if a subdural hematoma this is the space that gets filled with blood

Diencephalon

-top part of lollipop stick, completely inside of the cerebrum -divided into epithalamus, thalamus and hypothalamus

Choroid plexus

-vascularized membrane found inside all of the ventricles Plexus mean,a network

Temporal lobe

-we have auditory cortex and olfactory cortex relating to hearing and smell -if you pull back temporal lobe and look inside you find the insula inside the cerebrum

A normal adult replaces __________________ of CSF every 8 hours

150 millimeters

The CSF reduces the weight of the brain from

1500 grams to 50 grams, allows brain to float so it does not get crush on its own weight

______of CSF flows out through later and median apertures into the subarachnoid space

90%

What is the meninge that looks like a spider web?

Arachnoid mater

Inside ventricles we have?

CSF

when CSF reaches the fourth ventricle it can leave the ventricular system through which apertures?

Lateral aperture and Median aperture

What is capable of passing through the lipid bilayer?

Lipid soluble compounds

Cerebral cortex is divide into 3 layers:

Molecular layer is where we find dendrite of purkinje cells Purkinje layer is the intermediate layer where we find purkinje cell bodies Granular layer is the receptive layer where we find the axons of purkinje cells, we have tightly packed small neurons

What layer is found on the anterior fontanelle of a baby?

Periosteal layer

Where does the pituitary gland sit inside of?

Sella turcica What encases the sella turcica?,the diaphragma sellae Diaphragma sellae, -lines the sella turcica -Anchors dura mater to sphenoid bone -encases pituitary gland

The arachnoid valve works a

a one way valve

Precentral gyrus

also called primary motor cortex,in front of central sulcus, INITIATION of movement -region of the brain that sends the nerve impulses down the spinal cord towards the muscle when you want to make a movement -we find the pyramidal cells large which are the large neurons that allow the consciously control of skeletal muscle movements

Pineal gland

an endocrine that produces hormone called melatonin, that affects wake sleep patterns

Crista galli function

anchor brain

Premotor cortex

anterior to the primary motor cortex, related to PLANNING of motor movement Ex)thinking about grabbing a pen -premotor cortex send info to primary motor cortex

The third ventricle communicates with the fourth ventricle via the

aqueduct of mid brain also called cerebral aqueduct

Infundibulum

area that connects the hypothalamus to pituitary gland

What glial cell forms the BBB?

astrocytes

Cerebrum is part of our brain where we have the

awareness of our senses and can initiate the voluntary movements of our body

Central sulcus

between frontal lobe and parietal lobe

Parieto-occipital lobe

between parietal and occipital lobe

The fourth ventricle located

between the pons and cerebellum

CSF Superior sagittal sinus receives blood and CSf from?

blood from the cerebral veins and recieves CSF from the subarachnoid space via the arachnoid granulations

What do you not find in CSF?

blood proteins and red and white blood cells

Choroid

blood vessels

Corpus callosum

bundle of axons the decussate (cross) between two hemispheres and connect the two cerebrum hemispheres

The CSF give ____________to the CNS structures

buoyancy

Purkinje cells

cells responsible for our coordinated movements

the fourth ventricle of the brain communicates with the

central canal of the spinal cord

The remaining 10% continues to flow through a

central canal that runs through the entire spinal cord

The cerebellum communication with other regions of the brain happens via the

cerebellar peduncles -superior peduncles communicates cerebellum with mesencephalon, diencephalon and cerebrum -middle peduncles communicates cerebellum with the pons -inferior peduncles communicates cerebellum with medulla oblongata

Lateral Ventricles #1 and 2 located in the

cerebrum hemispheres

This directionality is due to

ciliated movement of ependymal cells

the lateral ventricles do not ___________ with each other

communicate there is no direct connection between the two,lateral ventricles

Association fibers are responsible for

connecting areas of the cerebrum cortex within the same hemisphere Ex)arcuate fibers and longitudinal fasciculi

What does the middle cerebellar peduncle do?

connects pons to cerebellum

The frontal lobe is related to

conscious control of skeletal muscles and trouble solving, reasoning and planning

Epithalamus

contains pineal gland Thalamus,- surrounds the third ventricle -right and left thalamus connected by interthalamic adhesion -relay station for all sensory info that comes through spinal cord and eyes and ears

What is a point of attachment in the inferior anterior aspect of the falx cerebri?

crista galli of ethmoid bone

If damage is in the brain stem it often means

death

Third ventricle located in the

diencephalon

Longitudinal fissure

divides right and left hemisphere of cerebrum

Tentorium cerebelli

dura mater fold located along transverse cerebral fissure (deep depression separating cerebrum from cerebellum)

Falx cerebelli

dura mater fold located between right and left hemisphere of cerebellum

Falx cerebri

dura mater fold located between right and left hemisphere of cerebrum, along the longitudinal fissure

What are the cranial meninges?

dura mater, arachnoid mater, pia mater

Blood vessels in the choroid plexus are surrounded by

ependymal cells

Dura septa

extensions of the dura mater that goes deep inside the brain

What are the commissural fibers?

fibers that connect the two cerebrum hemispheres Anterior commissure and corpus callosum

Transverse cerebral fissure

fissure (deep depression) between cerebrum and cerebellum

Ventricles

fluid filled cavities

Folia of cerebellum

folds of cerebellum equivalent to cerebrum gyri

Projection fibers

groups of axons link the cerebrum with other regions of the brain

In insula we find the __________

gustatory cortex which gives us the perception of taste

Meningitis

inflammation of meninges -causes increased amount of CSF

Where is CSF located?

inside the ventricles of the brain, inside central canal of spinal cord and surrounding brain and spinal cord

All ventricles are

interconnected

the veins of the brain empty themselves into the sinuses which deliver the blood to the

internal jugular vein in the neck

right and left thalamus are connected by the

interthalamic adhesion

The lateral ventricles communicates with the third ventricles via the

interventricular foramen

Intracranial pressure (ICP)

is the pressure exerted by fluids such as cerebrospinal fluid (CSF) inside the skull and on the brain tissue.

The hypothalamus is wired to the

limbic system the part of the brain involved in behavioral and emotional responses Ex) if we are upset it affects hypothalamus and causes it to make autonomic motor neurons to speed up our heart rate and raise our blood pressure, if relaxed BP goes down and heart rate

the reabsorption of the CSF involves the

meninges

Brainstem:

mesencephalon (midbrain), pons, medulla oblongata

What is another name for mesencephalon?

midbrain

White matter is composed of

myelintaed axons

Gray matter is composed of

neuronal cell bodies

If the CSF pressure is less than the pressure of the venous pressure the arachnoid villi will

not let the blood pass into the interventricular system

Dura mater is formed by what two layers:-Periosteal layer (closer to the skull) attaches to inner surface of skull

only found in brain -Meningeal layer (closer to arachnoid mater) extends into vertebral canal as the spinal dura mater

Each cerebral hemisphere controls the ___________ side of the body

opposite

Hypothalamus links the nervous system and the endocrine system via the

pituitary gland

hydrocephalus

results from -overproduction of CSF -obstruction within ventricular system -problems with CSF reabsorption

What happens when the two dura layers separate?

results in blood filled space dura venous sinus

If someone has a stroke on the primary cortex of the left hemisphere the person will develop an impairment on the _____________ of the body

right side

Primary fissure

separates anterior and posterior lobe of cerebellum

Lateral sulcus

separating temporal lobe from all other lobes

Lateral ventricles are separated by a partition called

septum pellucidum

Superior sagittal sinus

sinus we have between the right and left cerebral hemispheres in the superior side

Hydrocephalus happens in newborns because

skull bones are not fused yet -there is increased pressure causing head to become very large

What are the functions of the mesencephalon?

some extrinsic eye muscles, sight and auditory processing, associated reflex

Dura venous sinus

space filled with venous blood, majority of blood from brain drains into

Medulla oblongata is the place that makes the link between our

spinal cord and the brain regions

If the CSF pressure is greater than the venous pressure of the superior sagittal sinus the CSF will be

squeezed out of the subarachnoid space flowing into the blood stream and get reabsorbed

There is an opening at the bottom of spinal cord where CSF comes out and enters the

subarachnoid space

95% of sensory information goes through the ____________ and forwarded to where it's supposed to go

thalamus

what is the largest nuclei we have in the CNS?

thalamus has largest mass of neuronal cell bodies in the CNS

What do we have under the cranium?

the dura mater

The jugular vein that drains blood out of our brain gets the blood supply from

the dura venous sinuses

Infundibulum

the structure that connects the pituitary gland and the hypothalamus

Meningitis causes problems with reabsorption because

there is no communication between where the CSF is made and where it is reabsorbed causing Intracranial pressure to raise which is fatal

between the right and left thalamus we have the

third ventricle and the two thalami surround the 3rd ventricle

Capillary endothelial cells are attached by

tight junctions which block the passage of material between the cells

Treatment for hydrocephalus is

to drain CSF by making a small hole in ventricle and drain the CSF form ventricle in a place in the abdominal cavity

Cerebellum right and left hemisphere are separated by the

vermis

CSF is made up of

water, sugar, and electrolytes (gatorade)

When our blood pressure is low

what does the hypothalamus release?,antidiuretic

Cerebellar Cortex

when gray matter is on the surface, where we find neuronal cell bodies of Purkinje cells

Nuclei

when we have a group of neuronal cell bodies within the CNS

Cortex

when we have collection of neuronal cell bodies in the surface of the CNS

Arbor vitae

white matter of cerebellum, looks like tree of life